The gunsmith recommends to trim the bottom of the die to neck the casings more down. Will this work or not? Just started handloading.
He probably said to trim the bottom so you could bump the shoulder back more. I'm guessing you're hitting your shell holder with the bottom of the die and not bumping the shoulder back as far as you should be.
It happens more often than you think.
I have 2 dies that need to be shorter (1 Redding and 1 RCBS).